Page 32 - Enzymes in Tropical Soils

20 Enzymes In Tropical Soils

mutually interacted; the rate of a reaction increases with the increase in the
concentrations of these two substances. To eliminate the effect of substrate, the
substrate concentration is then maximized so that the rate of the reaction is
independent of substrate concentration and is dependent only on the
concentration of enzyme. At high concentration of substrate, the rate of a reaction
is constant independetn of substrate addition and follows the zero order kinetics as
shown in Fig. 2.3. K m in Fig. 2.3 is the substrate concentration (in moles per liter) at
half-maximum rate. V max equals to 2v.

V Max

v

v = ½ V max

K m [S]

Fig. 2.3. The relationship between the reaction rate and substrate concentration
(Tabatabai, 1982)

The rate constant is originated from Eq. 2.5 as follows. Differentiating Eq.
2.5 results in Eq. 2.6. It is shown by Eq. 2.6 that the rate of a biochemical reaction
at high concentration is constant and is independent of the substrate
concentration. Therefore, at high substrate concentration, the rate of a reaction
will be determined by the concentration of enzyme. The products resulted from an
enzymatic reaction will show the activity of particular enzyme, which will be higher
with the higher concentration of enzyme.

or x = kt ....... Eq. 2.5

....... Eq. 2.6

Abdul Kadir Salam - 2014